Energy efficient electrolyzer for the production of hydrogen

Abstract

Disclosed is an energy efficient electrolyzer for the production of hydrogen. The electrolyzer consists of an inner container, a plurality of electrolytic cells within the container and means for passing electric current in series through the electrolytic cells. Each cell consists of the anode half of one inert impervious conducting bipolar plate, in contact with an inert conductive anode bed of large surface area separated from the facing cathode half of another inert impervious conducting bipolar plate by a porous insulating separator. The anode is impregnated with an anolyte of about 10 to about 60% aqueous sulfuric acid saturated with sulfur dioxide and the cathode is bathed in a catholyte of about 10 to about 60% aqueous sulfuric acid. The anode is preferably carbon pellets which have been obtained from vegetable matter and which contain about 1 to about 5% platinum.

We claim: 
     
       1. An electrolyzer for the production of hydrogen comprising: (1) an inert container;   (2) a plurality of electrolytic cells within said container, each comprising (A) the anode half of one inert impervious conducting bipolar plate and the facing cathode half of another inert impervious conducting bipolar plate;   (B) an inert conductive anode bed of porous activated carbon pellets of large surface area on said anode half of said bipolar plate, said anode bed being impregnated with an anolyte which comprises about 10 to about 60% aqueous sulfuric acid saturated with sulfur dioxide;   (C) a porous separator, between said anode bed and said cathode half; and   (D) a catholyte which comprises about 10 to about 60% aqueous sulfuric acid between said separator and said cathode half.     
     
     
       2. An electrolyzer according to claim 1 wherein said separator is a microporous rubber membrane about 20 to about 30 mils thick. 
     
     
       3. An electrolyzer according to claim 1 wherein said carbon pellets are obtained from vegetable matter. 
     
     
       4. An electrolyzer according to claim 1 wherein said carbon pellets contain about 1 to about 5% platinum. 
     
     
       5. An electrolyzer according to claim 1 wherein said carbon pellets are about 1/8 to about 1/4 inches in size. 
     
     
       6. An electrolyzer according to claim 1 wherein said bipolar plate is titanium coated with metal oxides. 
     
     
       7. An electrolyzer according to claim 1 wherein said sulfur dioxide is under a pressure of about 1 to about 12 atmospheres. 
     
     
       8. An electrolyzer according to claim 1 wherein the concentration of said sulfuric acid is about 45 to about 55%. 
     
     
       9. An electrolyzer according to claim 1 wherein the concentration of said sulfuric acid is about 10 to about 20%. 
     
     
       10. An electrolyzer according to claim 1 including means for continually draining said anolyte and for continually adding fresh anolyte and means for draining said catholyte and for adding fresh catholyte. 
     
     
       11. An electrolyzer according to claim 10 wherein said anolyte and catholyte are added and drained by gravity. 
     
     
       12. An electrolyzer according to claim wherein the temperature of said anolyte is maintained at about 20° to about 60° C. 
     
     
       13. An electrolyzer according to claim 1 wherein the number of said electrolytic cells is about 50 to about 500 cells. 
     
     
       14. An electrolyzer according to claim 1 wherein said electrode bipolar plate is about 10 to about 20 mils thick. 
     
     
       15. An electrolyzer according to claim 1 wherein said anode bed has a surface area in excess of 10 m 2  /g.